Value of Serum Zinc in Diagnosing and Assessing Severity of Liver Disease in Children With Wilson Disease.

OBJECTIVES

Wilson disease (WD) is a rare inborn error of copper metabolism with diverse manifestations. There has been no study of zinc (Zn), the copper's antagonist, in WD diagnosis and severity so far. Our aims were to evaluate serum Zn in WD and its correlation with the disease severity score (revised WD index). Although the ATP7B mutation analysis is highly accurate for WD diagnosis, it may not be readily available in a resource-limiting setting. We proposed a disease diagnostic score (Proposed WD diagnostic score) which incorporates serum Zn.

METHODS

Medical records of WD and non-WD children seen at King's College Hospital from 2005 to 2015 were reviewed for the selected parameters using the Proposed WD diagnostic score. Available serum Zn data in WD children before disease diagnosis and the calculated severity score were statistically analyzed. Diagnostic values of the Proposed WD diagnostic score were evaluated.

RESULTS

Serum Zn level was significantly lower in 8 WD-acute liver failure (ALF) (5.8 [4.1-8.3] μmol/L) compared to 18 WD-non-ALF (13.5 [6.1-22.2] μmol/L) and 9 ALF from indeterminate cause (9.8 [7.0-12.1] μmol/L) (P < 0.001). Serum Zn significantly correlated with the revised WD index (r = -0.554, P = 0.004). The Proposed WD diagnostic score that included serum Zn level as 1 of the parameters had sensitivity and specificity of 87% and 99.2%, respectively.

CONCLUSIONS

Serum Zn is a novel parameter for diagnosis and correlates with severity of WD. The Proposed WD diagnostic score is useful while awaiting ATP7B mutation analysis.